1. Field of the Invention
The present invention is directed to compositions and methods for treating a disease or disorder and/or enhancing the immune system of a patient and, in particular, vaccines of non-naturally occurring substances and vaccination methods for treating and/or enhancing the immune system against infection by Mycobacterium tuberculosis. 
2. Description of the Background
Mycobacterium tuberculosis (MTB) is a pathogenic bacterial species in the family Mycobacteriaceae and the causative agent of most cases of tuberculosis (TB). Another species of this genus is M. leprae, the causative agent of leprosy. MTB was first discovered in 1882 by Robert Koch, M. tuberculosis has an unusual, complex, lipid rich, cell wall which makes the cells impervious to Gram staining. Acid-fast detection techniques are used to make the diagnosis instead. The physiology of M. tuberculosis is highly aerobic and requires significant levels of oxygen to remain viable. Primarily a pathogen of the mammalian respiratory system, MTB is generally inhaled and, in five to ten percent of individuals, will progress to an acute pulmonary infection. The remaining individuals will either clear the infection completely or the infection may become latent. It is not clear how the immune system controls MTB, but cell mediated immunity is believed to play a critical role (Svenson et al., Human Vaccines, 6-4:309-17, 2010). Common diagnostic methods for TB are the tuberculin skin test, acid-fast stain and chest radiographs.
M. tuberculosis requires oxygen to proliferate and does not retain typical bacteriological stains due to high lipid content of its cell wall. While mycobacteria do not fit the Gram-positive category from an empirical standpoint (i.e., they do not retain the crystal violet stain), they are classified as acid-fast Gram-positive bacteria due to their lack of an outer cell membrane.
M. tuberculosis has over one hundred strain variations and divides every 15-20 hours, which is extremely slow compared to other types of bacteria that have division times measured in minutes (Escherichia coli can divide roughly every 20 minutes). The microorganism is a small bacillus that can withstand weak disinfectants and survive in a dry state for weeks. The cell wall of MTB contains multiple components such as peptidoglycan, mycolic acid and the glycolipid lipoarabinomannan. The role of these moieties in pathogenesis and immunity remain controversial. (Svenson et al., Human Vaccines, 6-4:309-17, 2010).
When in the lungs, M. tuberculosis is taken up by alveolar macrophages, but these macrophages are unable to digest the bacteria because the cell wall of the bacteria prevents the fusion of the phagosome with a lysosome. Specifically, M. tuberculosis blocks the bridging molecule, early endosomal autoantigen 1 (EEA1); however, this blockade does not prevent fusion of vesicles filled with nutrients. As a consequence, bacteria multiply unchecked within the macrophage. The bacteria also carry the UreC gene, which prevents acidification of the phagosome, and also evade macrophage-killing by neutralizing reactive nitrogen intermediates.
The BCG vaccine (Bacille de Calmette et Guérin) against tuberculosis is prepared from a strain of the attenuated, but live bovine tuberculosis bacillus, Mycobacterium bovis. This strain lost its virulence to humans through in vitro subculturing in Middlebrook 7H9 media. As the bacteria adjust to subculturing conditions, including the chosen media, the organism adapts and in doing so, loses its natural growth characteristics for human blood. Consequently, the bacteria can no longer induce disease when introduced into a human host. However, the attenuated and virulent bacteria retain sufficient similarity to provide immunity against infection of human tuberculosis. The effectiveness of the BCG vaccine has been highly varied, with an efficacy of from zero to eighty percent in preventing tuberculosis for duration of fifteen years, although protection seems to vary greatly according to geography and the lab in which the vaccine strain was grown. This variation, which appears to depend on geography, generates a great deal of controversy over use of the BCG vaccine yet has been observed in many different clinical trials. For example, trials conducted in the United Kingdom have consistently shown a protective effect of sixty to eighty percent, but those conducted in other areas have shown no or almost no protective effect. For whatever reason, these trials all show that efficacy decreases in those clinical trials conducted close to the equator. In addition, although widely used because of its protective effects against disseminated TB and TB meningitis in children, the BCG vaccine is largely ineffective against adult pulmonary TB, the single most contagious form of TB.
A 1994 systematic review found that the BCG reduces the risk of getting TB by about fifty percent. There are differences in effectiveness, depending on region due to factors such as genetic differences in the populations, changes in environment, exposure to other bacterial infections, and conditions in the lab where the vaccine is grown, including genetic differences between the strains being cultured and the choice of growth medium.
The duration of protection of BCG is not clearly known or understood. In those studies showing a protective effect, the data are inconsistent. The MRC study showed protection waned to 59% after 15 years and to zero after 20 years; however, a study looking at Native Americans immunized in the 1930s found evidence of protection even 60 years after immunization, with only a slight waning in efficacy. Rigorous analysis of the results demonstrates that BCG has poor protection against adult pulmonary disease, but does provide good protection against disseminated disease and TB meningitis in children. Therefore there is a need for new vaccines and vaccine antigens that can provide solid and long-term immunity to MTB.
The role of antibodies in the development of immunity to MTB is controversial. Current data suggests that T cells, specifically CD4+ and CD8+ T cells, are critical for maximizing macrophage activity against MTB and promoting optimal control of infection (Slight et al, JCI 123(2):712, February 2013). However, these same authors demonstrated that B cell deficient mice are not more susceptible to MTB infection than B cell intact mice suggesting that humoral immunity is not critical. Phagocytosis of MTB can occur via surface opsonins, such as C3, or nonopsonized MTB surface mannose moieties. Fc gamma receptors, important for IgG facilitated phagocytosis, do not seem to play an important role in MTB immunity (Crevel et al., Clin Micro Rev. 15(2), April, 2002; Armstrong et al., J Exp Med. 1975 Jul. 1; 142(1):1-16). IgA has been considered for prevention and treatment of TB, since it is a mucosal antibody. A human IgA monoclonal antibody to the MTB heat shock protein HSPX (HSPX) given intra-nasally provided protection in a mouse model (Balu et al, J of Immun. 186:3113, 2011). Mice treated with IgA had less prominent MTB pneumonic infiltrates than untreated mice. While antibody prevention and therapy may be hopeful, the effective MTB antigen targets and the effective antibody class and subclasses have not been established (Acosta et al, Intech, 2013).
Cell wall components of MTB have been delineated and analyzed for many years. Lipoarabinomannan (LAM) has been shown to be a virulence factor and a monoclonal antibody to LAM has enhanced protection to MTB in mice (Teitelbaum, et al., Proc. Natl. Acad. Sci. 95:15688-15693, 1998, Svenson et al., Human Vaccines, 6-4:309-17, 2010). The mechanism whereby the MAB enhanced protection was not determined and the MAB did not decrease bacillary burden. It was postulated that the MAB possibly blocked the effects of LAM induced cytokines. The role of mycolic acid for vaccines and immune therapy is unknown. It has been used for diagnostic purposes, but has not been shown to have utility for vaccine or other immune therapy approaches. While MTB infected individuals may develop antibodies to mycolic acid, there is no evidence that antibodies in general, or specifically mycolic acid antibodies, play a role in immunity to MTB.
Antibiotic resistance is becoming more and more of a problem for treating MTB infections. The BCG vaccine against TB does not provide protection from acquiring TB to a significant degree. Thus there is a strong need to provide or improve products and approaches to prevent and treat MTB.